A driving condition monitoring and warning system for providing information on objects ahead of a vehicle to a driver is proposed in Japanese patent application document JP-A-11-139229. In this system, an object recognition level of the driver is determined and an alarm is produced if the driver has not recognized an object that may be necessary to be recognized for safe driving of the vehicle. The object recognition level indicates how well the driver has recognized existence of objects that are necessary to be recognized for safe driving of the vehicle mainly in a range of the driver's vision.
Although it is difficult for the driver to recognize all of the objects at once if a number of objects exist in the range of driver's vision, the system assumes that all objects in the range are recognized. As a result, an alarm will not be produced for an object in the range even if the object is not recognized by the driver.